﻿/* jQuery UI Date Picker v3.3 - previously jQuery Calendar
Written by Marc Grabanski (m@marcgrabanski.com) and Keith Wood (kbwood@virginbroadband.com.au).

Copyright (c) 2007 Marc Grabanski (http://marcgrabanski.com/code/ui-datepicker)
Dual licensed under the MIT (MIT-LICENSE.txt)
and GPL (GPL-LICENSE.txt) licenses.
Date: 09-03-2007  */

/* Date picker manager.
Use the singleton instance of this class, $.datepicker, to interact with the date picker.
Settings for (groups of) date pickers are maintained in an instance object
(DatepickerInstance), allowing multiple different settings on the same page. */

(function ($) { // hide the namespace

    function Datepicker() {
        this.debug = false; // Change this to true to start debugging
        this._nextId = 0; // Next ID for a date picker instance
        this._inst = []; // List of instances indexed by ID
        this._curInst = null; // The current instance in use
        this._disabledInputs = []; // List of date picker inputs that have been disabled
        this._datepickerShowing = false; // True if the popup picker is showing , false if not
        this._inDialog = false; // True if showing within a "dialog", false if not
        this.regional = []; // Available regional settings, indexed by language code
        this.regional[''] = { // Default regional settings
            clearText: 'Очистить', // Display text for clear link
            clearStatus: 'Стереть текущую дату', // Status text for clear link
            closeText: 'Закрыть', // Display text for close link
            closeStatus: 'Закрыть без сохранения', // Status text for close link
            prevText: '&#x3c;Пред', // Display text for previous month link
            prevStatus: 'Предыдущий месяц', // Status text for previous month link
            nextText: 'След&#x3e;', // Display text for next month link
            nextStatus: 'Следующий месяц', // Status text for next month link
            currentText: 'Сегодня', // Display text for current month link
            currentStatus: 'Текущий месяц', // Status text for current month link
            monthNames: ['Январь', 'Февраль', 'Март', 'Апрель', 'Май', 'Июнь',
            'Июль', 'Август', 'Сентябрь', 'Октябрь', 'Ноябрь', 'Декабрь'], // Names of months for drop-down and formatting
            monthNamesShort: ['Янв', 'Фев', 'Мар', 'Апр', 'Май', 'Июн', 'Июл', 'Авг', 'Сен', 'Окт', 'Ноя', 'Дек'], // For formatting
            monthStatus: 'Показать другой месяц', // Status text for selecting a month
            yearStatus: 'Показать другой год', // Status text for selecting a year
            weekHeader: 'Нед', // Header for the week of the year column
            weekStatus: 'Неделя года', // Status text for the week of the year column
            dayNames: ['Воскресенье', 'Понедельник', 'Вторник', 'Среда', 'Четверг', 'Пятница', 'Суббота'], // For formatting
            dayNamesShort: ['Вск', 'Пнд', 'Втр', 'Срд', 'Чтв', 'Птн', 'Сбт'], // For formatting
            dayNamesMin: ['Вс', 'Пн', 'Вт', 'Ср', 'Чт', 'Пт', 'Сб'], // Column headings for days starting at Sunday
            dayStatus: 'Установить первым днем недели', // Status text for the day of the week selection
            dateStatus: 'Выбрать день, месяц, год', // Status text for the date selection
            dateFormat: 'dd.mm.yy', // See format options on parseDate
            firstDay: 1, // The first day of the week, Sun = 0, Mon = 1, ...
            initStatus: 'Выбрать дату', // Initial Status text on opening
            isRTL: false // True if right-to-left language, false if left-to-right
        };
        this._defaults = { // Global defaults for all the date picker instances
            showOn: 'focus', // 'focus' for popup on focus,
            // 'button' for trigger button, or 'both' for either
            showAnim: 'show', // Name of jQuery animation for popup
            defaultDate: null, // Used when field is blank: actual date,
            // +/-number for offset from today, null for today
            appendText: '', // Display text following the input box, e.g. showing the format
            buttonText: '...', // Text for trigger button
            buttonImage: '', // URL for trigger button image
            buttonImageOnly: false, // True if the image appears alone, false if it appears on a button
            closeAtTop: true, // True to have the clear/close at the top,
            // false to have them at the bottom
            mandatory: false, // True to hide the Clear link, false to include it
            hideIfNoPrevNext: false, // True to hide next/previous month links
            // if not applicable, false to just disable them
            changeMonth: true, // True if month can be selected directly, false if only prev/next
            changeYear: true, // True if year can be selected directly, false if only prev/next
            yearRange: '-10:+10', // Range of years to display in drop-down,
            // either relative to current year (-nn:+nn) or absolute (nnnn:nnnn)
            changeFirstDay: true, // True to click on day name to change, false to remain as set
            showOtherMonths: false, // True to show dates in other months, false to leave blank
            showWeeks: false, // True to show week of the year, false to omit
            calculateWeek: this.iso8601Week, // How to calculate the week of the year,
            // takes a Date and returns the number of the week for it
            shortYearCutoff: '+10', // Short year values < this are in the current century,
            // > this are in the previous century, 
            // string value starting with '+' for current year + value
            showStatus: false, // True to show status bar at bottom, false to not show it
            statusForDate: this.dateStatus, // Function to provide status text for a date -
            // takes date and instance as parameters, returns display text
            minDate: null, // The earliest selectable date, or null for no limit
            maxDate: null, // The latest selectable date, or null for no limit
            speed: 'medium', // Speed of display/closure
            beforeShowDay: null, // Function that takes a date and returns an array with
            // [0] = true if selectable, false if not,
            // [1] = custom CSS class name(s) or '', e.g. $.datepicker.noWeekends
            beforeShow: null, // Function that takes an input field and
            // returns a set of custom settings for the date picker
            onSelect: null, // Define a callback function when a date is selected
            numberOfMonths: 1, // Number of months to show at a time
            stepMonths: 1, // Number of months to step back/forward
            rangeSelect: false, // Allows for selecting a date range on one date picker
            rangeSeparator: ' - ' // Text between two dates in a range
        };
        $.extend(this._defaults, this.regional['']);
        this._datepickerDiv = $('<div id="datepicker_div"></div>');
    }

    $.extend(Datepicker.prototype, {
        /* Class name added to elements to indicate already configured with a date picker. */
        markerClassName: 'hasDatepicker',

        /* Debug logging (if enabled). */
        log: function () {
            if (this.debug) {
                console.log.apply('', arguments);
            }
        },

        /* Register a new date picker instance - with custom settings. */
        _register: function (inst) {
            var id = this._nextId++;
            this._inst[id] = inst;
            return id;
        },

        /* Retrieve a particular date picker instance based on its ID. */
        _getInst: function (id) {
            return this._inst[id] || id;
        },

        /* Override the default settings for all instances of the date picker. 
        @param  settings  object - the new settings to use as defaults (anonymous object)
        @return the manager object */
        setDefaults: function (settings) {
            extendRemove(this._defaults, settings || {});
            return this;
        },

        /* Handle keystrokes. */
        _doKeyDown: function (e) {
            var inst = $.datepicker._getInst(this._calId);
            if ($.datepicker._datepickerShowing) {
                switch (e.keyCode) {
                    case 9: $.datepicker.hideDatepicker('');
                        break; // hide on tab out
                    case 13: $.datepicker._selectDay(inst, inst._selectedMonth, inst._selectedYear,
                            $('td.datepicker_daysCellOver', inst._datepickerDiv)[0]);
                        return false; // don't submit the form
                        break; // select the value on enter
                    case 27: $.datepicker.hideDatepicker(inst._get('speed'));
                        break; // hide on escape
                    case 33: $.datepicker._adjustDate(inst,
                            (e.ctrlKey ? -1 : -inst._get('stepMonths')), (e.ctrlKey ? 'Y' : 'M'));
                        break; // previous month/year on page up/+ ctrl
                    case 34: $.datepicker._adjustDate(inst,
                            (e.ctrlKey ? +1 : +inst._get('stepMonths')), (e.ctrlKey ? 'Y' : 'M'));
                        break; // next month/year on page down/+ ctrl
                    case 35: if (e.ctrlKey) $.datepicker._clearDate(inst);
                        break; // clear on ctrl+end
                    case 36: if (e.ctrlKey) $.datepicker._gotoToday(inst);
                        break; // current on ctrl+home
                    case 37: if (e.ctrlKey) $.datepicker._adjustDate(inst, -1, 'D');
                        break; // -1 day on ctrl+left
                    case 38: if (e.ctrlKey) $.datepicker._adjustDate(inst, -7, 'D');
                        break; // -1 week on ctrl+up
                    case 39: if (e.ctrlKey) $.datepicker._adjustDate(inst, +1, 'D');
                        break; // +1 day on ctrl+right
                    case 40: if (e.ctrlKey) $.datepicker._adjustDate(inst, +7, 'D');
                        break; // +1 week on ctrl+down
                }
            }
            else if (e.keyCode == 36 && e.ctrlKey) { // display the date picker on ctrl+home
                $.datepicker.showFor(this);
            }
        },

        /* Filter entered characters - based on date format. */
        _doKeyPress: function (e) {
            var inst = $.datepicker._getInst(this._calId);
            var chars = $.datepicker._possibleChars(inst._get('dateFormat'));
            var chr = String.fromCharCode(e.charCode == undefined ? e.keyCode : e.charCode);
            return (chr < ' ' || !chars || chars.indexOf(chr) > -1);
        },

        /* Attach the date picker to an input field. */
        _connectDatepicker: function (target, inst) {
            var input = $(target);
            if (this._hasClass(input, this.markerClassName)) {
                return;
            }
            var appendText = inst._get('appendText');
            var isRTL = inst._get('isRTL');
            if (appendText) {
                if (isRTL) {
                    input.before('<span class="datepicker_append">' + appendText + '</span>');
                }
                else {
                    input.after('<span class="datepicker_append">' + appendText + '</span>');
                }
            }
            var showOn = inst._get('showOn');
            if (showOn == 'focus' || showOn == 'both') { // pop-up date picker when in the marked field
                input.focus(this.showFor);
            }
            if (showOn == 'button' || showOn == 'both') { // pop-up date picker when button clicked
                var buttonText = inst._get('buttonText');
                var buttonImage = inst._get('buttonImage');
                var buttonImageOnly = inst._get('buttonImageOnly');
                var trigger = $(buttonImageOnly ? '<img class="datepicker_trigger" src="' +
                buttonImage + '" alt="' + buttonText + '" title="' + buttonText + '"/>' :
                '<button type="button" class="datepicker_trigger">' + (buttonImage != '' ?
                '<img src="' + buttonImage + '" alt="' + buttonText + '" title="' + buttonText + '"/>' :
                buttonText) + '</button>');
                input.wrap('<span class="datepicker_wrap"></span>');
                if (isRTL) {
                    input.before(trigger);
                }
                else {
                    input.after(trigger);
                }
                trigger.click(this.showFor);
            }
            input.addClass(this.markerClassName).keydown(this._doKeyDown).keypress(this._doKeyPress);
            input[0]._calId = inst._id;
        },

        /* Attach an inline date picker to a div. */
        _inlineDatepicker: function (target, inst) {
            var input = $(target);
            if (this._hasClass(input, this.markerClassName)) {
                return;
            }
            input.addClass(this.markerClassName).append(inst._datepickerDiv);
            input[0]._calId = inst._id;
            this._updateDatepicker(inst);
            /* @todo: fix _inlineShow automatic resizing
            - Endless loop bug in IE6.  
            - inst._datepickerDiv.resize doesn't ever fire in firefox.  */
            // inst._datepickerDiv.resize(function() { $.datepicker._inlineShow(inst); });
        },

        /* Tidy up after displaying the date picker. */
        _inlineShow: function (inst) {
            var numMonths = inst._getNumberOfMonths(); // fix width for dynamic number of date pickers
            inst._datepickerDiv.width(numMonths[1] * $('.datepicker', inst._datepickerDiv[0]).width());
        },

        /* Does this element have a particular class? */
        _hasClass: function (element, className) {
            var classes = element.attr('class');
            return (classes && classes.indexOf(className) > -1);
        },

        /* Pop-up the date picker in a "dialog" box.
        @param  dateText  string - the initial date to display (in the current format)
        @param  onSelect  function - the function(dateText) to call when a date is selected
        @param  settings  object - update the dialog date picker instance's settings (anonymous object)
        @param  pos       int[2] - coordinates for the dialog's position within the screen or
        event - with x/y coordinates or
        leave empty for default (screen centre)
        @return the manager object */
        dialogDatepicker: function (dateText, onSelect, settings, pos) {
            var inst = this._dialogInst; // internal instance
            if (!inst) {
                inst = this._dialogInst = new DatepickerInstance({}, false);
                this._dialogInput = $('<input type="text" size="1" style="position: absolute; top: -100px;"/>');
                this._dialogInput.keydown(this._doKeyDown);
                $('body').append(this._dialogInput);
                this._dialogInput[0]._calId = inst._id;
            }
            extendRemove(inst._settings, settings || {});
            this._dialogInput.val(dateText);

            this._pos = (pos ? (pos.length ? pos : [pos.pageX, pos.pageY]) : null);
            if (!this._pos) {
                var browserWidth = window.innerWidth || document.documentElement.clientWidth ||
                document.body.clientWidth;
                var browserHeight = window.innerHeight || document.documentElement.clientHeight ||
                document.body.clientHeight;
                var scrollX = document.documentElement.scrollLeft || document.body.scrollLeft;
                var scrollY = document.documentElement.scrollTop || document.body.scrollTop;
                this._pos = // should use actual width/height below
                [(browserWidth / 2) - 100 + scrollX, (browserHeight / 2) - 150 + scrollY];
            }

            // move input on screen for focus, but hidden behind dialog
            this._dialogInput.css('left', this._pos[0] + 'px').css('top', this._pos[1] + 'px');
            inst._settings.onSelect = onSelect;
            this._inDialog = true;
            this._datepickerDiv.addClass('datepicker_dialog');
            this.showFor(this._dialogInput[0]);
            if ($.blockUI) {
                $.blockUI(this._datepickerDiv);
            }
            return this;
        },

        /* Pop-up the date picker for a given input field.
        @param  control  element - the input field attached to the date picker or
        string - the ID or other jQuery selector of the input field or
        object - jQuery object for input field
        @return the manager object */
        showFor: function (control) {
            control = (control.jquery ? control[0] :
            (typeof control == 'string' ? $(control)[0] : control));
            var input = (control.nodeName && control.nodeName.toLowerCase() == 'input' ? control : this);
            if (input.nodeName.toLowerCase() != 'input') { // find from button/image trigger
                input = $('input', input.parentNode)[0];
            }
            if ($.datepicker._lastInput == input) { // already here
                return;
            }
            if ($(input).isDisabledDatepicker()) {
                return;
            }
            var inst = $.datepicker._getInst(input._calId);
            var beforeShow = inst._get('beforeShow');
            extendRemove(inst._settings, (beforeShow ? beforeShow.apply(input, [input, inst]) : {}));
            $.datepicker.hideDatepicker('');
            $.datepicker._lastInput = input;
            inst._setDateFromField(input);
            if ($.datepicker._inDialog) { // hide cursor
                input.value = '';
            }
            if (!$.datepicker._pos) { // position below input
                $.datepicker._pos = $.datepicker._findPos(input);
                $.datepicker._pos[1] += input.offsetHeight; // add the height
            }
            var isFixed = false;
            $(input).parents().each(function () {
                isFixed |= $(this).css('position') == 'fixed';
            });
            if (isFixed && $.browser.opera) { // correction for Opera when fixed and scrolled
                $.datepicker._pos[0] -= document.documentElement.scrollLeft;
                $.datepicker._pos[1] -= document.documentElement.scrollTop;
            }
            inst._datepickerDiv.css('position', ($.datepicker._inDialog && $.blockUI ?
            'static' : (isFixed ? 'fixed' : 'absolute'))).
            css('left', $.datepicker._pos[0] + 'px').css('top', $.datepicker._pos[1] + 'px').
            css('z-index', '3000');
            $.datepicker._pos = null;
            $.datepicker._showDatepicker(inst);
            return this;
        },

        /* Construct and display the date picker. */
        _showDatepicker: function (id) {
            var inst = this._getInst(id);
            inst._rangeStart = null;
            this._updateDatepicker(inst);
            if (!inst._inline) {
                var speed = inst._get('speed');
                var postProcess = function () {
                    $.datepicker._datepickerShowing = true;
                    $.datepicker._afterShow(inst);
                };
                var showAnim = inst._get('showAnim') || 'show';
                inst._datepickerDiv[showAnim](speed, postProcess);
                if (speed == '') {
                    postProcess();
                }
                if (inst._input[0].type != 'hidden') {
                    inst._input[0].focus();
                }
                this._curInst = inst;
            }
        },

        /* Generate the date picker content. */
        _updateDatepicker: function (inst) {
            inst._datepickerDiv.empty().append(inst._generateDatepicker());
            var numMonths = inst._getNumberOfMonths();
            if (numMonths[0] != 1 || numMonths[1] != 1) {
                inst._datepickerDiv.addClass('datepicker_multi');
            }
            else {
                inst._datepickerDiv.removeClass('datepicker_multi');
            }
            if (inst._get('isRTL')) {
                inst._datepickerDiv.addClass('datepicker_rtl');
            }
            else {
                inst._datepickerDiv.removeClass('datepicker_rtl');
            }
            if (inst._input && inst._input[0].type != 'hidden') {
                inst._input[0].focus();
            }
        },

        /* Tidy up after displaying the date picker. */
        _afterShow: function (inst) {
            var numMonths = inst._getNumberOfMonths(); // fix width for dynamic number of date pickers
            inst._datepickerDiv.width(numMonths[1] * $('.datepicker', inst._datepickerDiv[0]).width());
            if ($.browser.msie && parseInt($.browser.version) < 7) { // fix IE < 7 select problems
                $('#datepicker_cover').css({ width: inst._datepickerDiv.width() + 4,
                    height: inst._datepickerDiv.height() + 4
                });
            }
            // re-position on screen if necessary
            var isFixed = inst._datepickerDiv.css('position') == 'fixed';
            var pos = inst._input ? $.datepicker._findPos(inst._input[0]) : null;
            var browserWidth = window.innerWidth || document.documentElement.clientWidth ||
            document.body.clientWidth;
            var browserHeight = window.innerHeight || document.documentElement.clientHeight ||
            document.body.clientHeight;
            var scrollX = (isFixed ? 0 : document.documentElement.scrollLeft || document.body.scrollLeft);
            var scrollY = (isFixed ? 0 : document.documentElement.scrollTop || document.body.scrollTop);
            // reposition date picker horizontally if outside the browser window
            if ((inst._datepickerDiv.offset().left + inst._datepickerDiv.width() -
                (isFixed && $.browser.msie ? document.documentElement.scrollLeft : 0)) >
                (browserWidth + scrollX)) {
                inst._datepickerDiv.css('left', Math.max(scrollX,
                pos[0] + (inst._input ? $(inst._input[0]).width() : null) - inst._datepickerDiv.width() -
                (isFixed && $.browser.opera ? document.documentElement.scrollLeft : 0)) + 'px');
            }
            // reposition date picker vertically if outside the browser window
            if ((inst._datepickerDiv.offset().top + inst._datepickerDiv.height() -
                (isFixed && $.browser.msie ? document.documentElement.scrollTop : 0)) >
                (browserHeight + scrollY)) {
                inst._datepickerDiv.css('top', Math.max(scrollY,
                pos[1] - (this._inDialog ? 0 : inst._datepickerDiv.height()) -
                (isFixed && $.browser.opera ? document.documentElement.scrollTop : 0)) + 'px');
            }
        },

        /* Find an object's position on the screen. */
        _findPos: function (obj) {
            while (obj && (obj.type == 'hidden' || obj.nodeType != 1)) {
                obj = obj.nextSibling;
            }
            var curleft = curtop = 0;
            if (obj && obj.offsetParent) {
                curleft = obj.offsetLeft;
                curtop = obj.offsetTop;
                while (obj = obj.offsetParent) {
                    var origcurleft = curleft;
                    curleft += obj.offsetLeft;
                    if (curleft < 0) {
                        curleft = origcurleft;
                    }
                    curtop += obj.offsetTop;
                }
            }
            return [curleft, curtop];
        },

        /* Hide the date picker from view.
        @param  speed  string - the speed at which to close the date picker
        @return void */
        hideDatepicker: function (speed) {
            var inst = this._curInst;
            if (!inst) {
                return;
            }
            var rangeSelect = inst._get('rangeSelect');
            if (rangeSelect && this._stayOpen) {
                this._selectDate(inst, inst._formatDate(
                inst._currentDay, inst._currentMonth, inst._currentYear));
            }
            this._stayOpen = false;
            if (this._datepickerShowing) {
                speed = (speed != null ? speed : inst._get('speed'));
                inst._datepickerDiv.hide(speed, function () {
                    $.datepicker._tidyDialog(inst);
                });
                if (speed == '') {
                    this._tidyDialog(inst);
                }
                this._datepickerShowing = false;
                this._lastInput = null;
                inst._settings.prompt = null;
                if (this._inDialog) {
                    this._dialogInput.css('position', 'absolute').
                    css('left', '0px').css('top', '-100px');
                    if ($.blockUI) {
                        $.unblockUI();
                        $('body').append(this._datepickerDiv);
                    }
                }
                this._inDialog = false;
            }
            this._curInst = null;
        },

        /* Tidy up after a dialog display. */
        _tidyDialog: function (inst) {
            inst._datepickerDiv.removeClass('datepicker_dialog');
            $('.datepicker_prompt', inst._datepickerDiv).remove();
        },

        /* Close date picker if clicked elsewhere. */
        _checkExternalClick: function (event) {
            if (!$.datepicker._curInst) {
                return;
            }
            var target = $(event.target);
            if ((target.parents("#datepicker_div").length == 0) &&
                (target.attr('class') != 'datepicker_trigger') &&
                $.datepicker._datepickerShowing && !($.datepicker._inDialog && $.blockUI)) {
                $.datepicker.hideDatepicker('');
            }
        },

        /* Adjust one of the date sub-fields. */
        _adjustDate: function (id, offset, period) {
            var inst = this._getInst(id);
            inst._adjustDate(offset, period);
            this._updateDatepicker(inst);
        },

        /* Action for current link. */
        _gotoToday: function (id) {
            var date = new Date();
            var inst = this._getInst(id);
            inst._selectedDay = date.getDate();
            inst._selectedMonth = date.getMonth();
            inst._selectedYear = date.getFullYear();
            this._adjustDate(inst);
        },

        /* Action for selecting a new month/year. */
        _selectMonthYear: function (id, select, period) {
            var inst = this._getInst(id);
            inst._selectingMonthYear = false;
            inst[period == 'M' ? '_selectedMonth' : '_selectedYear'] =
            select.options[select.selectedIndex].value - 0;
            this._adjustDate(inst);
        },

        /* Restore input focus after not changing month/year. */
        _clickMonthYear: function (id) {
            var inst = this._getInst(id);
            if (inst._input && inst._selectingMonthYear && !$.browser.msie) {
                inst._input[0].focus();
            }
            inst._selectingMonthYear = !inst._selectingMonthYear;
        },

        /* Action for changing the first week day. */
        _changeFirstDay: function (id, day) {
            var inst = this._getInst(id);
            inst._settings.firstDay = day;
            this._updateDatepicker(inst);
        },

        /* Action for selecting a day. */
        _selectDay: function (id, month, year, td) {
            if (this._hasClass($(td), 'datepicker_unselectable')) {
                return;
            }
            var inst = this._getInst(id);
            var rangeSelect = inst._get('rangeSelect');
            if (rangeSelect) {
                if (!this._stayOpen) {
                    $('.datepicker td').removeClass('datepicker_currentDay');
                    $(td).addClass('datepicker_currentDay');
                }
                this._stayOpen = !this._stayOpen;
            }
            inst._currentDay = $('a', td).html();
            inst._currentMonth = month;
            inst._currentYear = year;
            this._selectDate(id, inst._formatDate(
            inst._currentDay, inst._currentMonth, inst._currentYear));
            if (this._stayOpen) {
                inst._endDay = inst._endMonth = inst._endYear = null;
                inst._rangeStart = new Date(inst._currentYear, inst._currentMonth, inst._currentDay);
                this._updateDatepicker(inst);
            }
            else if (rangeSelect) {
                inst._endDay = inst._currentDay;
                inst._endMonth = inst._currentMonth;
                inst._endYear = inst._currentYear;
                inst._selectedDay = inst._currentDay = inst._rangeStart.getDate();
                inst._selectedMonth = inst._currentMonth = inst._rangeStart.getMonth();
                inst._selectedYear = inst._currentYear = inst._rangeStart.getFullYear();
                inst._rangeStart = null;
                if (inst._inline) {
                    this._updateDatepicker(inst);
                }
            }
        },

        /* Erase the input field and hide the date picker. */
        _clearDate: function (id) {
            var inst = this._getInst(id);
            this._stayOpen = false;
            inst._endDay = inst._endMonth = inst._endYear = inst._rangeStart = null;
            this._selectDate(inst, '');
        },

        /* Update the input field with the selected date. */
        _selectDate: function (id, dateStr) {
            var inst = this._getInst(id);
            dateStr = (dateStr != null ? dateStr : inst._formatDate());
            if (inst._rangeStart) {
                dateStr = inst._formatDate(inst._rangeStart) + inst._get('rangeSeparator') + dateStr;
            }
            if (inst._input) {
                inst._input.val(dateStr);
            }
            var onSelect = inst._get('onSelect');
            if (onSelect) {
                onSelect.apply((inst._input ? inst._input[0] : null), [dateStr, inst]);  // trigger custom callback
            }
            else {
                if (inst._input) {
                    inst._input.trigger('change'); // fire the change event
                }
            }
            if (inst._inline) {
                this._updateDatepicker(inst);
            }
            else {
                if (!this._stayOpen) {
                    this.hideDatepicker(inst._get('speed'));
                    this._lastInput = inst._input[0];
                    if (typeof (inst._input[0]) != 'object') {
                        inst._input[0].focus(); // restore focus
                    }
                    this._lastInput = null;
                }
            }
        },

        /* Set as beforeShowDay function to prevent selection of weekends.
        @param  date  Date - the date to customise
        @return [boolean, string] - is this date selectable?, what is its CSS class? */
        noWeekends: function (date) {
            var day = date.getDay();
            return [(day > 0 && day < 6), ''];
        },

        /* Set as calculateWeek to determine the week of the year based on the ISO 8601 definition.
        @param  date  Date - the date to get the week for
        @return  number - the number of the week within the year that contains this date */
        iso8601Week: function (date) {
            var checkDate = new Date(date.getFullYear(), date.getMonth(), date.getDate());
            var firstMon = new Date(checkDate.getFullYear(), 1 - 1, 4); // First week always contains 4 Jan
            var firstDay = firstMon.getDay() || 7; // Day of week: Mon = 1, ..., Sun = 7
            firstMon.setDate(firstMon.getDate() + 1 - firstDay); // Preceding Monday
            if (firstDay < 4 && checkDate < firstMon) { // Adjust first three days in year if necessary
                checkDate.setDate(checkDate.getDate() - 3); // Generate for previous year
                return $.datepicker.iso8601Week(checkDate);
            }
            else if (checkDate > new Date(checkDate.getFullYear(), 12 - 1, 28)) { // Check last three days in year
                firstDay = new Date(checkDate.getFullYear() + 1, 1 - 1, 4).getDay() || 7;
                if (firstDay > 4 && (checkDate.getDay() || 7) < firstDay - 3) { // Adjust if necessary
                    checkDate.setDate(checkDate.getDate() + 3); // Generate for next year
                    return $.datepicker.iso8601Week(checkDate);
                }
            }
            return Math.floor(((checkDate - firstMon) / 86400000) / 7) + 1; // Weeks to given date
        },

        /* Provide status text for a particular date.
        @param  date  the date to get the status for
        @param  inst  the current datepicker instance
        @return  the status display text for this date */
        dateStatus: function (date, inst) {
            return $.datepicker.formatDate(inst._get('dateStatus'), date, inst._get('dayNamesShort'),
            inst._get('dayNames'), inst._get('monthNamesShort'), inst._get('monthNames'));
        },

        /* Parse a string value into a date object.
        The format can be combinations of the following:
        d  - day of month (no leading zero)
        dd - day of month (two digit)
        D  - day name short
        DD - day name long
        m  - month of year (no leading zero)
        mm - month of year (two digit)
        M  - month name short
        MM - month name long
        y  - year (two digit)
        yy - year (four digit)
        '...' - literal text
        '' - single quote

        @param  format           String - the expected format of the date
        @param  value            String - the date in the above format
        @param  shortYearCutoff  Number - the cutoff year for determining the century (optional)
        @param  dayNamesShort    String[7] - abbreviated names of the days from Sunday (optional)
        @param  dayNames         String[7] - names of the days from Sunday (optional)
        @param  monthNamesShort  String[12] - abbreviated names of the months (optional)
        @param  monthNames       String[12] - names of the months (optional)
        @return  Date - the extracted date value or null if value is blank */
        parseDate: function (format, value, shortYearCutoff, dayNamesShort, dayNames, monthNamesShort, monthNames) {
            if (format == null || value == null) {
                throw 'Invalid arguments';
            }
            //      format = dateFormats[format] || format;
            value = (typeof value == 'object' ? value.toString() : value + '');
            if (value == '') {
                return null;
            }
            dayNamesShort = dayNamesShort || this._defaults.dayNamesShort;
            dayNames = dayNames || this._defaults.dayNames;
            monthNamesShort = monthNamesShort || this._defaults.monthNamesShort;
            monthNames = monthNames || this._defaults.monthNames;
            var year = -1;
            var month = -1;
            var day = -1;
            var literal = false;
            // Check whether a format character is doubled
            var lookAhead = function (match) {
                var matches = (iFormat + 1 < format.length && format.charAt(iFormat + 1) == match);
                if (matches) {
                    iFormat++;
                }
                return matches;
            };
            // Extract a number from the string value
            var getNumber = function (match) {
                lookAhead(match);
                var size = (match == 'y' ? 4 : 2);
                var num = 0;
                while (size > 0 && iValue < value.length &&
                    value.charAt(iValue) >= '0' && value.charAt(iValue) <= '9') {
                    num = num * 10 + (value.charAt(iValue++) - 0);
                    size--;
                }
                if (size == (match == 'y' ? 4 : 2)) {
                    throw 'Missing number at position ' + iValue;
                }
                return num;
            };
            // Extract a name from the string value and convert to an index
            var getName = function (match, shortNames, longNames) {
                var names = (lookAhead(match) ? longNames : shortNames);
                var size = 0;
                for (var j = 0; j < names.length; j++) {
                    size = Math.max(size, names[j].length);
                }
                var name = '';
                var iInit = iValue;
                while (size > 0 && iValue < value.length) {
                    name += value.charAt(iValue++);
                    for (var i = 0; i < names.length; i++) {
                        if (name == names[i]) {
                            return i + 1;
                        }
                    }
                    size--;
                }
                throw 'Unknown name at position ' + iInit;
            };
            // Confirm that a literal character matches the string value
            var checkLiteral = function () {
                if (value.charAt(iValue) != format.charAt(iFormat)) {
                    throw 'Unexpected literal at position ' + iValue;
                }
                iValue++;
            };
            var iValue = 0;
            for (var iFormat = 0; iFormat < format.length; iFormat++) {
                if (literal) {
                    if (format.charAt(iFormat) == '\'' && !lookAhead('\'')) {
                        literal = false;
                    }
                    else {
                        checkLiteral();
                    }
                }
                else {
                    switch (format.charAt(iFormat)) {
                        case 'd':
                            day = getNumber('d');
                            break;
                        case 'D':
                            getName('D', dayNamesShort, dayNames);
                            break;
                        case 'm':
                            month = getNumber('m');
                            break;
                        case 'M':
                            month = getName('M', monthNamesShort, monthNames);
                            break;
                        case 'y':
                            year = getNumber('y');
                            break;
                        case '\'':
                            if (lookAhead('\'')) {
                                checkLiteral();
                            }
                            else {
                                literal = true;
                            }
                            break;
                        default:
                            checkLiteral();
                    }
                }
            }
            if (year < 100) {
                year += new Date().getFullYear() - new Date().getFullYear() % 100 +
                (year <= shortYearCutoff ? 0 : -100);
            }
            var date = new Date(year, month - 1, day);
            if (date.getFullYear() != year || date.getMonth() + 1 != month || date.getDate() != day) {
                throw 'Invalid date'; // E.g. 31/02/*
            }
            return date;
        },

        /* Format a date object into a string value.
        The format can be combinations of the following:
        d  - day of month (no leading zero)
        dd - day of month (two digit)
        D  - day name short
        DD - day name long
        m  - month of year (no leading zero)
        mm - month of year (two digit)
        M  - month name short
        MM - month name long
        y  - year (two digit)
        yy - year (four digit)
        '...' - literal text
        '' - single quote

        @param  format           String - the desired format of the date
        @param  date             Date - the date value to format
        @param  dayNamesShort    String[7] - abbreviated names of the days from Sunday (optional)
        @param  dayNames         String[7] - names of the days from Sunday (optional)
        @param  monthNamesShort  String[12] - abbreviated names of the months (optional)
        @param  monthNames       String[12] - names of the months (optional)
        @return  String - the date in the above format */
        formatDate: function (format, date, dayNamesShort, dayNames, monthNamesShort, monthNames) {
            if (!date) {
                return '';
            }
            //      format = dateFormats[format] || format;
            dayNamesShort = dayNamesShort || this._defaults.dayNamesShort;
            dayNames = dayNames || this._defaults.dayNames;
            monthNamesShort = monthNamesShort || this._defaults.monthNamesShort;
            monthNames = monthNames || this._defaults.monthNames;
            // Check whether a format character is doubled
            var lookAhead = function (match) {
                var matches = (iFormat + 1 < format.length && format.charAt(iFormat + 1) == match);
                if (matches) {
                    iFormat++;
                }
                return matches;
            };
            // Format a number, with leading zero if necessary
            var formatNumber = function (match, value) {
                return (lookAhead(match) && value < 10 ? '0' : '') + value;
            };
            // Format a name, short or long as requested
            var formatName = function (match, value, shortNames, longNames) {
                return (lookAhead(match) ? longNames[value] : shortNames[value]);
            };
            var output = '';
            var literal = false;
            if (date) {
                for (var iFormat = 0; iFormat < format.length; iFormat++) {
                    if (literal) {
                        if (format.charAt(iFormat) == '\'' && !lookAhead('\'')) {
                            literal = false;
                        }
                        else {
                            output += format.charAt(iFormat);
                        }
                    }
                    else {
                        switch (format.charAt(iFormat)) {
                            case 'd':
                                output += formatNumber('d', date.getDate());
                                break;
                            case 'D':
                                output += formatName('D', date.getDay(), dayNamesShort, dayNames);
                                break;
                            case 'm':
                                output += formatNumber('m', date.getMonth() + 1);
                                break;
                            case 'M':
                                output += formatName('M', date.getMonth(), monthNamesShort, monthNames);
                                break;
                            case 'y':
                                output += (lookAhead('y') ? date.getFullYear() :
                                (date.getYear() % 100 < 10 ? '0' : '') + date.getYear() % 100);
                                break;
                            case '\'':
                                if (lookAhead('\'')) {
                                    output += '\'';
                                }
                                else {
                                    literal = true;
                                }
                                break;
                            default:
                                output += format.charAt(iFormat);
                        }
                    }
                }
            }
            return output;
        },

        /* Extract all possible characters from the date format. */
        _possibleChars: function (format) {
            //      format = dateFormats[format] || format;
            var chars = '';
            var literal = false;
            for (var iFormat = 0; iFormat < format.length; iFormat++) {
                if (literal) {
                    if (format.charAt(iFormat) == '\'' && !lookAhead('\'')) {
                        literal = false;
                    }
                    else {
                        chars += format.charAt(iFormat);
                    }
                }
                else {
                    switch (format.charAt(iFormat)) {
                        case 'd':
                        case 'm':
                        case 'y':
                            chars += '0123456789';
                            break;
                        case 'D':
                        case 'M':
                            return null; // Accept anything
                        case '\'':
                            if (lookAhead('\'')) {
                                chars += '\'';
                            }
                            else {
                                literal = true;
                            }
                            break;
                        default:
                            chars += format.charAt(iFormat);
                    }
                }
            }
            return chars;
        }
    });

    /* Individualised settings for date picker functionality applied to one or more related inputs.
    Instances are managed and manipulated through the Datepicker manager. */
    function DatepickerInstance(settings, inline) {
        this._id = $.datepicker._register(this);
        this._selectedDay = 0;
        this._selectedMonth = 0; // 0-11
        this._selectedYear = 0; // 4-digit year
        this._input = null; // The attached input field
        this._inline = inline; // True if showing inline, false if used in a popup
        this._datepickerDiv = (!inline ? $.datepicker._datepickerDiv :
        $('<div id="datepicker_div_' + this._id + '" class="datepicker_inline"></div>'));
        // customise the date picker object - uses manager defaults if not overridden
        this._settings = extendRemove({}, settings || {}); // clone
        if (inline) {
            this._setDate(this._getDefaultDate());
        }
    }

    $.extend(DatepickerInstance.prototype, {
        /* Get a setting value, defaulting if necessary. */
        _get: function (name) {
            return (this._settings[name] != null ? this._settings[name] : $.datepicker._defaults[name]);
        },

        /* Parse existing date and initialise date picker. */
        _setDateFromField: function (input) {
            this._input = $(input);
            var dateFormat = this._get('dateFormat');
            var dates = this._input ? this._input.val().split(this._get('rangeSeparator')) : null;
            this._endDay = this._endMonth = this._endYear = null;
            var shortYearCutoff = this._get('shortYearCutoff');
            shortYearCutoff = (typeof shortYearCutoff != 'string' ? shortYearCutoff :
            new Date().getFullYear() % 100 + parseInt(shortYearCutoff, 10));
            var date = defaultDate = this._getDefaultDate();
            if (dates.length > 0) {
                var dayNamesShort = this._get('dayNamesShort');
                var dayNames = this._get('dayNames');
                var monthNamesShort = this._get('monthNamesShort');
                var monthNames = this._get('monthNames');
                if (dates.length > 1) {
                    date = $.datepicker.parseDate(dateFormat, dates[1], shortYearCutoff,
                    dayNamesShort, dayNames, monthNamesShort, monthNames) || defaultDate;
                    this._endDay = date.getDate();
                    this._endMonth = date.getMonth();
                    this._endYear = date.getFullYear();
                }
                try {
                    date = $.datepicker.parseDate(dateFormat, dates[0], shortYearCutoff,
                    dayNamesShort, dayNames, monthNamesShort, monthNames) || defaultDate;
                }
                catch (e) {
                    $.datepicker.log(e);
                    date = defaultDate;
                }
            }
            this._selectedDay = this._currentDay = date.getDate();
            this._selectedMonth = this._currentMonth = date.getMonth();
            this._selectedYear = this._currentYear = date.getFullYear();
            this._adjustDate();
        },

        /* Retrieve the default date shown on opening. */
        _getDefaultDate: function () {
            return this._determineDate('defaultDate', new Date());
        },

        /* A date may be specified as an exact value or a relative one. */
        _determineDate: function (name, defaultDate) {
            var offsetNumeric = function (offset) {
                var date = new Date();
                date.setDate(date.getDate() + offset);
                return date;
            };
            var offsetString = function (offset, getDaysInMonth) {
                var date = new Date();
                var matches = /^([+-]?[0-9]+)\s*(d|D|w|W|m|M|y|Y)?$/.exec(offset);
                if (matches) {
                    var year = date.getFullYear();
                    var month = date.getMonth();
                    var day = date.getDate();
                    switch (matches[2] || 'd') {
                        case 'd': case 'D':
                            day += (matches[1] - 0); break;
                        case 'w': case 'W':
                            day += (matches[1] * 7); break;
                        case 'm': case 'M':
                            month += (matches[1] - 0);
                            day = Math.min(day, getDaysInMonth(year, month));
                            break;
                        case 'y': case 'Y':
                            year += (matches[1] - 0);
                            day = Math.min(day, getDaysInMonth(year, month));
                            break;
                    }
                    date = new Date(year, month, day);
                }
                return date;
            };
            var date = this._get(name);
            return (date == null ? defaultDate :
            (typeof date == 'string' ? offsetString(date, this._getDaysInMonth) :
            (typeof date == 'number' ? offsetNumeric(date) : date)));
        },

        /* Set the date(s) directly. */
        _setDate: function (date, endDate) {
            this._selectedDay = this._currentDay = date.getDate();
            this._selectedMonth = this._currentMonth = date.getMonth();
            this._selectedYear = this._currentYear = date.getFullYear();
            if (this._get('rangeSelect')) {
                if (endDate) {
                    this._endDay = endDate.getDate();
                    this._endMonth = endDate.getMonth();
                    this._endYear = endDate.getFullYear();
                }
                else {
                    this._endDay = this._currentDay;
                    this._endMonth = this._currentMonth;
                    this._endYear = this._currentYear;
                }
            }
            this._adjustDate();
        },

        /* Retrieve the date(s) directly. */
        _getDate: function () {
            var startDate = (!this._currentYear || (this._input && this._input.val() == '') ? null :
            new Date(this._currentYear, this._currentMonth, this._currentDay));
            if (this._get('rangeSelect')) {
                return [startDate, (!this._endYear ? null :
                new Date(this._endYear, this._endMonth, this._endDay))];
            }
            else {
                return startDate;
            }
        },

        /* Generate the HTML for the current state of the date picker. */
        _generateDatepicker: function () {
            var today = new Date();
            today = new Date(today.getFullYear(), today.getMonth(), today.getDate()); // clear time
            var showStatus = this._get('showStatus');
            var isRTL = this._get('isRTL');
            // build the date picker HTML
            var clear = (this._get('mandatory') ? '' :
            '<div class="datepicker_clear"><a onclick="jQuery.datepicker._clearDate(' + this._id + ');"' +
            (showStatus ? this._addStatus(this._get('clearStatus') || '&#xa0;') : '') + '>' +
            this._get('clearText') + '</a></div>');
            var controls = '<div class="datepicker_control">' + (isRTL ? '' : clear) +
            '<div class="datepicker_close"><a onclick="jQuery.datepicker.hideDatepicker();"' +
            (showStatus ? this._addStatus(this._get('closeStatus') || '&#xa0;') : '') + '>' +
            this._get('closeText') + '</a></div>' + (isRTL ? clear : '') + '</div>';
            var prompt = this._get('prompt');
            var closeAtTop = this._get('closeAtTop');
            var hideIfNoPrevNext = this._get('hideIfNoPrevNext');
            var numMonths = this._getNumberOfMonths();
            var stepMonths = this._get('stepMonths');
            var isMultiMonth = (numMonths[0] != 1 || numMonths[1] != 1);
            var minDate = this._getMinMaxDate('min', true);
            var maxDate = this._getMinMaxDate('max');
            var drawMonth = this._selectedMonth;
            var drawYear = this._selectedYear;
            if (maxDate) {
                var maxDraw = new Date(maxDate.getFullYear(),
                maxDate.getMonth() - numMonths[1] + 1, maxDate.getDate());
                maxDraw = (minDate && maxDraw < minDate ? minDate : maxDraw);
                while (new Date(drawYear, drawMonth, 1) > maxDraw) {
                    drawMonth--;
                    if (drawMonth < 0) {
                        drawMonth = 11;
                        drawYear--;
                    }
                }
            }
            // controls and links
            var prev = '<div class="datepicker_prev">' + (this._canAdjustMonth(-1, drawYear, drawMonth) ?
            '<a onclick="jQuery.datepicker._adjustDate(' + this._id + ', -' + stepMonths + ', \'M\');"' +
            (showStatus ? this._addStatus(this._get('prevStatus') || '&#xa0;') : '') + '>' +
            this._get('prevText') + '</a>' :
            (hideIfNoPrevNext ? '' : '<label>' + this._get('prevText') + '</label>')) + '</div>';
            var next = '<div class="datepicker_next">' + (this._canAdjustMonth(+1, drawYear, drawMonth) ?
            '<a onclick="jQuery.datepicker._adjustDate(' + this._id + ', +' + stepMonths + ', \'M\');"' +
            (showStatus ? this._addStatus(this._get('nextStatus') || '&#xa0;') : '') + '>' +
            this._get('nextText') + '</a>' :
            (hideIfNoPrevNext ? '>' : '<label>' + this._get('nextText') + '</label>')) + '</div>';
            var html = (prompt ? '<div class="datepicker_prompt">' + prompt + '</div>' : '') +
            (closeAtTop && !this._inline ? controls : '') +
            '<div class="datepicker_links">' + (isRTL ? next : prev) +
            (this._isInRange(today) ? '<div class="datepicker_current">' +
            '<a onclick="jQuery.datepicker._gotoToday(' + this._id + ');"' +
            (showStatus ? this._addStatus(this._get('currentStatus') || '&#xa0;') : '') + '>' +
            this._get('currentText') + '</a></div>' : '') + (isRTL ? prev : next) + '</div>';
            var showWeeks = this._get('showWeeks');
            for (var row = 0; row < numMonths[0]; row++) {
                for (var col = 0; col < numMonths[1]; col++) {
                    var selectedDate = new Date(drawYear, drawMonth, this._selectedDay);
                    html += '<div class="datepicker_oneMonth' + (col == 0 ? ' datepicker_newRow' : '') + '">' +
                this._generateMonthYearHeader(drawMonth, drawYear, minDate, maxDate,
                selectedDate, row > 0 || col > 0) + // draw month headers
                '<table class="datepicker" cellpadding="0" cellspacing="0"><thead>' +
                '<tr class="datepicker_titleRow">' +
                (showWeeks ? '<td>' + this._get('weekHeader') + '</td>' : '');
                    var firstDay = this._get('firstDay');
                    var changeFirstDay = this._get('changeFirstDay');
                    var dayNames = this._get('dayNames');
                    var dayNamesShort = this._get('dayNamesShort');
                    var dayNamesMin = this._get('dayNamesMin');
                    for (var dow = 0; dow < 7; dow++) { // days of the week
                        var day = (dow + firstDay) % 7;
                        var status = this._get('dayStatus') || '&#xa0;';
                        status = (status.indexOf('DD') > -1 ? status.replace(/DD/, dayNames[day]) :
                    status.replace(/D/, dayNamesShort[day]));
                        html += '<td' + ((dow + firstDay + 6) % 7 >= 5 ? ' class="datepicker_weekEndCell"' : '') + '>' +
                    (!changeFirstDay ? '<span' :
                    '<a onclick="jQuery.datepicker._changeFirstDay(' + this._id + ', ' + day + ');"') +
                    (showStatus ? this._addStatus(status) : '') + ' title="' + dayNames[day] + '">' +
                    dayNamesMin[day] + (changeFirstDay ? '</a>' : '</span>') + '</td>';
                    }
                    html += '</tr></thead><tbody>';
                    var daysInMonth = this._getDaysInMonth(drawYear, drawMonth);
                    if (drawYear == this._selectedYear && drawMonth == this._selectedMonth) {
                        this._selectedDay = Math.min(this._selectedDay, daysInMonth);
                    }
                    var leadDays = (this._getFirstDayOfMonth(drawYear, drawMonth) - firstDay + 7) % 7;
                    var currentDate = new Date(this._currentYear, this._currentMonth, this._currentDay);
                    var endDate = this._endDay ? new Date(this._endYear, this._endMonth, this._endDay) : currentDate;
                    var printDate = new Date(drawYear, drawMonth, 1 - leadDays);
                    var numRows = (isMultiMonth ? 6 : Math.ceil((leadDays + daysInMonth) / 7)); // calculate the number of rows to generate
                    var beforeShowDay = this._get('beforeShowDay');
                    var showOtherMonths = this._get('showOtherMonths');
                    var calculateWeek = this._get('calculateWeek') || $.datepicker.iso8601Week;
                    var dateStatus = this._get('statusForDate') || $.datepicker.dateStatus;
                    for (var dRow = 0; dRow < numRows; dRow++) { // create date picker rows
                        html += '<tr class="datepicker_daysRow">' +
                    (showWeeks ? '<td class="datepicker_weekCol">' + calculateWeek(printDate) + '</td>' : '');
                        for (var dow = 0; dow < 7; dow++) { // create date picker days
                            var daySettings = (beforeShowDay ?
                        beforeShowDay.apply((this._input ? this._input[0] : null), [printDate]) : [true, '']);
                            var otherMonth = (printDate.getMonth() != drawMonth);
                            var unselectable = otherMonth || !daySettings[0] ||
                        (minDate && printDate < minDate) || (maxDate && printDate > maxDate);
                            html += '<td class="datepicker_daysCell' +
                        ((dow + firstDay + 6) % 7 >= 5 ? ' datepicker_weekEndCell' : '') + // highlight weekends
                        (otherMonth ? ' datepicker_otherMonth' : '') + // highlight days from other months
                        (printDate.getTime() == selectedDate.getTime() && drawMonth == this._selectedMonth ?
                        ' datepicker_daysCellOver' : '') + // highlight selected day
                        (unselectable ? ' datepicker_unselectable' : '') +  // highlight unselectable days
                        (otherMonth && !showOtherMonths ? '' : ' ' + daySettings[1] + // highlight custom dates
                        (printDate.getTime() >= currentDate.getTime() && printDate.getTime() <= endDate.getTime() ?  // in current range
                        ' datepicker_currentDay' : // highlight selected day
                        (printDate.getTime() == today.getTime() ? ' datepicker_today' : ''))) + '"' + // highlight today (if different)
                        (unselectable ? '' : ' onmouseover="jQuery(this).addClass(\'datepicker_daysCellOver\');' +
                        (!showStatus || (otherMonth && !showOtherMonths) ? '' : 'jQuery(\'#datepicker_status_' +
                        this._id + '\').html(\'' + (dateStatus.apply((this._input ? this._input[0] : null),
                        [printDate, this]) || '&#xa0;') + '\');') + '"' +
                        ' onmouseout="jQuery(this).removeClass(\'datepicker_daysCellOver\');' +
                        (!showStatus || (otherMonth && !showOtherMonths) ? '' : 'jQuery(\'#datepicker_status_' +
                        this._id + '\').html(\'&#xa0;\');') + '" onclick="jQuery.datepicker._selectDay(' +
                        this._id + ',' + drawMonth + ',' + drawYear + ', this);"') + '>' + // actions
                        (otherMonth ? (showOtherMonths ? printDate.getDate() : '&#xa0;') : // display for other months
                        (unselectable ? printDate.getDate() : '<a>' + printDate.getDate() + '</a>')) + '</td>'; // display for this month
                            printDate.setDate(printDate.getDate() + 1);
                        }
                        html += '</tr>';
                    }
                    drawMonth++;
                    if (drawMonth > 11) {
                        drawMonth = 0;
                        drawYear++;
                    }
                    html += '</tbody></table></div>';
                }
            }
            html += (showStatus ? '<div id="datepicker_status_' + this._id +
            '" class="datepicker_status">' + (this._get('initStatus') || '&#xa0;') + '</div>' : '') +
            (!closeAtTop && !this._inline ? controls : '') +
            '<div style="clear: both;"></div>' +
            ($.browser.msie && parseInt($.browser.version) < 7 && !this._inline ?
            '<iframe src="javascript:false;" class="datepicker_cover"></iframe>' : '');
            return html;
        },

        /* Generate the month and year header. */
        _generateMonthYearHeader: function (drawMonth, drawYear, minDate, maxDate, selectedDate, secondary) {
            minDate = (this._rangeStart && minDate && selectedDate < minDate ? selectedDate : minDate);
            var showStatus = this._get('showStatus');
            var html = '<div class="datepicker_header">';
            // month selection
            var monthNames = this._get('monthNames');
            if (secondary || !this._get('changeMonth')) {
                html += monthNames[drawMonth] + '&#xa0;';
            }
            else {
                var inMinYear = (minDate && minDate.getFullYear() == drawYear);
                var inMaxYear = (maxDate && maxDate.getFullYear() == drawYear);
                html += '<select class="datepicker_newMonth" ' +
                'onchange="jQuery.datepicker._selectMonthYear(' + this._id + ', this, \'M\');" ' +
                'onclick="jQuery.datepicker._clickMonthYear(' + this._id + ');"' +
                (showStatus ? this._addStatus(this._get('monthStatus') || '&#xa0;') : '') + '>';
                for (var month = 0; month < 12; month++) {
                    if ((!inMinYear || month >= minDate.getMonth()) &&
                        (!inMaxYear || month <= maxDate.getMonth())) {
                        html += '<option value="' + month + '"' +
                        (month == drawMonth ? ' selected="selected"' : '') +
                        '>' + monthNames[month] + '</option>';
                    }
                }
                html += '</select>';
            }
            // year selection
            if (secondary || !this._get('changeYear')) {
                html += drawYear;
            }
            else {
                // determine range of years to display
                var years = this._get('yearRange').split(':');
                var year = 0;
                var endYear = 0;
                if (years.length != 2) {
                    year = drawYear - 10;
                    endYear = drawYear + 10;
                }
                else if (years[0].charAt(0) == '+' || years[0].charAt(0) == '-') {
                    year = drawYear + parseInt(years[0], 10);
                    endYear = drawYear + parseInt(years[1], 10);
                }
                else {
                    year = parseInt(years[0], 10);
                    endYear = parseInt(years[1], 10);
                }
                year = (minDate ? Math.max(year, minDate.getFullYear()) : year);
                endYear = (maxDate ? Math.min(endYear, maxDate.getFullYear()) : endYear);
                html += '<select class="datepicker_newYear" ' +
                'onchange="jQuery.datepicker._selectMonthYear(' + this._id + ', this, \'Y\');" ' +
                'onclick="jQuery.datepicker._clickMonthYear(' + this._id + ');"' +
                (showStatus ? this._addStatus(this._get('yearStatus') || '&#xa0;') : '') + '>';
                for (; year <= endYear; year++) {
                    html += '<option value="' + year + '"' +
                    (year == drawYear ? ' selected="selected"' : '') +
                    '>' + year + '</option>';
                }
                html += '</select>';
            }
            html += '</div>'; // Close datepicker_header
            return html;
        },

        /* Provide code to set and clear the status panel. */
        _addStatus: function (text) {
            return ' onmouseover="jQuery(\'#datepicker_status_' + this._id + '\').html(\'' + text + '\');" ' +
            'onmouseout="jQuery(\'#datepicker_status_' + this._id + '\').html(\'&#xa0;\');"';
        },

        /* Adjust one of the date sub-fields. */
        _adjustDate: function (offset, period) {
            var year = this._selectedYear + (period == 'Y' ? offset : 0);
            var month = this._selectedMonth + (period == 'M' ? offset : 0);
            var day = Math.min(this._selectedDay, this._getDaysInMonth(year, month)) +
            (period == 'D' ? offset : 0);
            var date = new Date(year, month, day);
            // ensure it is within the bounds set
            var minDate = this._getMinMaxDate('min', true);
            var maxDate = this._getMinMaxDate('max');
            date = (minDate && date < minDate ? minDate : date);
            date = (maxDate && date > maxDate ? maxDate : date);
            this._selectedDay = date.getDate();
            this._selectedMonth = date.getMonth();
            this._selectedYear = date.getFullYear();
        },

        /* Determine the number of months to show. */
        _getNumberOfMonths: function () {
            var numMonths = this._get('numberOfMonths');
            return (numMonths == null ? [1, 1] : (typeof numMonths == 'number' ? [1, numMonths] : numMonths));
        },

        /* Determine the current maximum date - ensure no time components are set - may be overridden for a range. */
        _getMinMaxDate: function (minMax, checkRange) {
            var date = this._determineDate(minMax + 'Date', null);
            if (date) {
                date.setHours(0);
                date.setMinutes(0);
                date.setSeconds(0);
                date.setMilliseconds(0);
            }
            return date || (checkRange ? this._rangeStart : null);
        },

        /* Find the number of days in a given month. */
        _getDaysInMonth: function (year, month) {
            return 32 - new Date(year, month, 32).getDate();
        },

        /* Find the day of the week of the first of a month. */
        _getFirstDayOfMonth: function (year, month) {
            return new Date(year, month, 1).getDay();
        },

        /* Determines if we should allow a "next/prev" month display change. */
        _canAdjustMonth: function (offset, curYear, curMonth) {
            var numMonths = this._getNumberOfMonths();
            var date = new Date(curYear, curMonth + (offset < 0 ? offset : numMonths[1]), 1);
            if (offset < 0) {
                date.setDate(this._getDaysInMonth(date.getFullYear(), date.getMonth()));
            }
            return this._isInRange(date);
        },

        /* Is the given date in the accepted range? */
        _isInRange: function (date) {
            // during range selection, use minimum of selected date and range start
            var newMinDate = (!this._rangeStart ? null :
            new Date(this._selectedYear, this._selectedMonth, this._selectedDay));
            newMinDate = (newMinDate && this._rangeStart < newMinDate ? this._rangeStart : newMinDate);
            var minDate = newMinDate || this._getMinMaxDate('min');
            var maxDate = this._getMinMaxDate('max');
            return ((!minDate || date >= minDate) && (!maxDate || date <= maxDate));
        },

        /* Format the given date for display. */
        _formatDate: function (day, month, year) {
            if (!day) {
                this._currentDay = this._selectedDay;
                this._currentMonth = this._selectedMonth;
                this._currentYear = this._selectedYear;
            }
            var date = (day ? (typeof day == 'object' ? day : new Date(year, month, day)) :
            new Date(this._currentYear, this._currentMonth, this._currentDay));
            return $.datepicker.formatDate(this._get('dateFormat'), date,
            this._get('dayNamesShort'), this._get('dayNames'),
            this._get('monthNamesShort'), this._get('monthNames'));
        }
    });

    /* jQuery extend now ignores nulls! */
    function extendRemove(target, props) {
        $.extend(target, props);
        for (var name in props) {
            if (props[name] == null) {
                target[name] = null;
            }
        }
        return target;
    };

    /* Attach the date picker to a jQuery selection.
    @param  settings  object - the new settings to use for this date picker instance (anonymous)
    @return jQuery object - for chaining further calls */
    $.fn.attachDatepicker = function (settings) {
        return this.each(function () {
            // check for settings on the control itself - in namespace 'date:'
            var inlineSettings = null;
            for (attrName in $.datepicker._defaults) {
                var attrValue = this.getAttribute('date:' + attrName);
                if (attrValue) {
                    inlineSettings = inlineSettings || {};
                    try {
                        inlineSettings[attrName] = eval(attrValue);
                    }
                    catch (err) {
                        inlineSettings[attrName] = attrValue;
                    }
                }
            }
            var nodeName = this.nodeName.toLowerCase();
            if (nodeName == 'input') {
                var instSettings = (inlineSettings ? $.extend($.extend({}, settings || {}),
                inlineSettings || {}) : settings); // clone and customise
                var inst = (inst && !inlineSettings ? inst :
                new DatepickerInstance(instSettings, false));
                $.datepicker._connectDatepicker(this, inst);
            }
            else if (nodeName == 'div' || nodeName == 'span') {
                var instSettings = $.extend($.extend({}, settings || {}),
                inlineSettings || {}); // clone and customise
                var inst = new DatepickerInstance(instSettings, true);
                $.datepicker._inlineDatepicker(this, inst);
            }
        });
    };

    /* Detach a datepicker from its control.
    @return jQuery object - for chaining further calls */
    $.fn.removeDatepicker = function () {
        var jq = this.each(function () {
            var $this = $(this);
            var nodeName = this.nodeName.toLowerCase();
            var calId = this._calId;
            this._calId = null;
            if (nodeName == 'input') {
                $this.siblings('.datepicker_append').replaceWith('');
                $this.siblings('.datepicker_trigger').replaceWith('');
                $this.removeClass($.datepicker.markerClassName).
                unbind('focus', $.datepicker.showFor).
                unbind('keydown', $.datepicker._doKeyDown).
                unbind('keypress', $.datepicker._doKeyPress);
                var wrapper = $this.parents('.datepicker_wrap');
                if (wrapper) {
                    wrapper.replaceWith(wrapper.html());
                }
            }
            else if (nodeName == 'div' || nodeName == 'span') {
                $this.removeClass($.datepicker.markerClassName).empty();
            }
            if ($('input[_calId=' + calId + ']').length == 0) {
                // clean up if last for this ID
                $.datepicker._inst[calId] = null;
            }
        });
        if ($('input.hasDatepicker').length == 0) {
            // clean up if last input 
            $.datepicker._datepickerDiv.replaceWith('');
        }
        return jq;
    };

    /* Enable the date picker to a jQuery selection.
    @return jQuery object - for chaining further calls */
    $.fn.enableDatepicker = function () {
        return this.each(function () {
            this.disabled = false;
            $(this).siblings('button.datepicker_trigger').each(function () { this.disabled = false; });
            $(this).siblings('img.datepicker_trigger').css({ opacity: '1.0', cursor: '' });
            var $this = this;
            $.datepicker._disabledInputs = $.map($.datepicker._disabledInputs,
            function (value) { return (value == $this ? null : value); }); // delete entry
        });
    };

    /* Disable the date picker to a jQuery selection.
    @return jQuery object - for chaining further calls */
    $.fn.disableDatepicker = function () {
        return this.each(function () {
            this.disabled = true;
            $(this).siblings('button.datepicker_trigger').each(function () { this.disabled = true; });
            $(this).siblings('img.datepicker_trigger').css({ opacity: '0.5', cursor: 'default' });
            var $this = this;
            $.datepicker._disabledInputs = $.map($.datepicker._disabledInputs,
            function (value) { return (value == $this ? null : value); }); // delete entry
            $.datepicker._disabledInputs[$.datepicker._disabledInputs.length] = this;
        });
    };

    /* Is the first field in a jQuery collection disabled as a datepicker?
    @return boolean - true if disabled, false if enabled */
    $.fn.isDisabledDatepicker = function () {
        if (this.length == 0) {
            return false;
        }
        for (var i = 0; i < $.datepicker._disabledInputs.length; i++) {
            if ($.datepicker._disabledInputs[i] == this[0]) {
                return true;
            }
        }
        return false;
    };

    /* Update the settings for a date picker attached to an input field or division.
    @param  name   string - the name of the setting to change
    object - the new settings to update
    @param  value  any - the new value for the setting (omit if above is a map)
    @return jQuery object - for chaining further calls */
    $.fn.changeDatepicker = function (name, value) {
        var settings = name || {};
        if (typeof name == 'string') {
            settings = {};
            settings[name] = value;
        }
        return this.each(function () {
            var inst = $.datepicker._getInst(this._calId);
            if (inst) {
                extendRemove(inst._settings, settings);
                $.datepicker._updateDatepicker(inst);
            }
        });
    };

    /* Show the date picker attached to the first entry in a jQuery selection.
    @return jQuery object - for chaining further calls */
    $.fn.showDatepicker = function () {
        $.datepicker.showFor(this);
        return this;
    };

    /* Set the dates for a jQuery selection.
    @param  date     Date - the new date
    @param  endDate  Date - the new end date for a range (optional)
    @return jQuery object - for chaining further calls */
    $.fn.setDatepickerDate = function (date, endDate) {
        return this.each(function () {
            var inst = $.datepicker._getInst(this._calId);
            if (inst) {
                inst._setDate(date, endDate);
                $.datepicker._updateDatepicker(inst);
            }
        });
    };

    /* Get the date(s) for the first entry in a jQuery selection.
    @return Date - the current date or
    Date[2] - the current dates for a range*/
    $.fn.getDatepickerDate = function () {
        var inst = (this.length > 0 ? $.datepicker._getInst(this[0]._calId) : null);
        return (inst ? inst._getDate() : null);
    };

    /* Initialise the date picker. */
    $(document).ready(function () {
        $.datepicker = new Datepicker(); // singleton instance
        $(document.body).append($.datepicker._datepickerDiv).
        mousedown($.datepicker._checkExternalClick);
    });

})(jQuery);
